>But this interrupt on change is only valid for pins configured as inputs.

>I have implemented portB with inputs and outputs, the inputs configured "to
>interrupt on change" as i require, I am monitoring for stray interrupts
>(using leds) and so far, emphasis on so far no random problems/errors,

The problem is that any instruction that writes to the output bits of the port
also does an inherent read of the port as well. If the input bits of the port
happen to change while this output instruction is in progress, then you will
have a missed interrupt.

I have not actually had occasion to use this function, but someone posted some
test code here a while back to prove that the situation exists. It is also not
explained that well in the Microchip documentation, (in case it looks like an FU
by them I think) which is why some of the other comments in this thread.

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